The HTC One's Camera Compared

Updated 27/3/13: We have updated this feature twice; once on the 26th to clarify that there will be no camera firmware update in April, and secondly on the 27th with new information about the HTC One's mysterious performance at ISO 800 (and a possible firmware update in April). Both updates can be found on the Conclusion page.

The HTC One's 4MP Camera Compared

One of the major selling points of the HTC One that we recently reviewed is its camera technology. While we've given you some basic information about what it's about in our review, we did mention that we would dissect its camera performance in detail and that we'll deliver in this article.

Take note that this article is to examine and understand what HTC One has implemented in their new phone and it's not a camera phone performance shootout (which we'll save for another dedicated feature article). As such, we didn't gather every major new phone in the market for this comparison. For this article, we've chosen a few key phones (HTC One XL, iPhone 5, Nokia Pureview 808 and Nokia Lumia 920) that can help us understand where the HTC One stands and how has it improved or detracted against them.

What's an Ultrapixel?

HTC calls the camera technology on the One 'ultrapixels', but all that means is that the photosites on the sensor are larger by design, rather by limitation. Instead of piling on the megapixels on the same small sensor, which would make each individual photosite smaller, HTC has constrained the megapixel count to 4MP, making each photosite larger. HTC explains it quite easily in the graphic below. The photosite is measured in micrometers, and HTC is showing how the One's 4µm photosite is larger than its competitors' photosites.

Size Does Matter...Sometimes

In theory, larger photosites should make the sensor more sensitive to light, producing images with less noise and higher dynamic range. But photosite size is just one part of the picture (excuse us). Like we said in our Nokia 808 PureView feature:

Improvements in image quality can be made from advances to sensor technology and image processing. This isn't impossible; more megapixels have been crammed into digital compact cameras over the years while sensor sizes have remained constant, and some manufacturers have been able to do it while retaining image quality. Nikon's latest D800 DSLR camera shoots at 36MP, whereas its predecessor the D700 shot 12MP images with the same sensor size, and Nikon is claiming even better image quality than before.

In other words, you can bump image quality through better sensor design, image processing and optics, and get the same or better image quality even with smaller photosites.

And of course, with less megapixels you sacrifice image detail - there are less pixels to 'draw' the same amount of information as a similarly-sized sensor with more pixels. Remember that a digital image is composed of individual dots, or pixels. The more there are, the finer your images can be. Just look at the difference between the 8-bit NES graphics of yesterday and today's full-HD PlayStation 3 games.

Wikipedia comes to the rescue again, with this easy-to-understand illustration of the difference in resolution you can get with more pixels:

So how much 'canvas' is the HTC One sacrificing? Take a look at the graphic below to see. At 4MP, it has half the pixel resolution (not sensor size) compared to an 8MP camera like the HTC One XL and the iPhone 5.

Now, with the preamble out of the way, let's take a look at the HTC One's camera and see if it lives up to the marketing. But first, a specs sheet for you to devour.

What a Difference a Firmware Update Makes

Updated 26/3/13: HTC has clarified that the second unit which we received "has the final commercial firmware, compared to the original unit which was pre-production and had an isolated hardware issue, which resulted in differences between the two sets of photos taken with both devices." According to our understanding, all the commercial sets which will launch in April will come already updated with this firmware. As such, there will be no second camera update for the One, unlike what we previously wrote below.

While we were halfway through reviewing the HTC One's camera, HTC called and swapped out our One with one (cough, cough) which had a firmware update for the camera. The update made a noticeable difference in the quality of the photos, as you can see for yourself below in the 100% crops. Images are sharper, with more detail. A visible softness in the upper left and bottom right corners, which we attributed to poor lens construction, has cleared up.

There's still something unusual happening with ISO 800 however. With both the older One and the One with the firmware update, image quality at ISO 800 takes a sudden dip; details are softer and the image is noisier than both ISO 400 and ISO 1600.

Unless otherwise stated, we'll be using the updated HTC One for the rest of this camera review. HTC says that there will be a firmware update for the general public in April. As such, what we present you is what you can expect out of the phone, if it has been updated.